1. Field of the Invention
The invention is directed to apparatus and methods for drying crops and specifically to the heating apparatus and methods employed for bulk curing of tobacco.
2. Description of the Prior Art
Apparatus and methods for bulk curing of tobacco and for drying other crops by circulation of heated air through the crops have been well documented in numerous prior patents. U.S. Pat. Nos. 3,105,713; 3,910,757; 3,972,674 and 3,999,303 are cited by way of example.
It has also been known to utilize a single pressurized heating source for curing tobacco or other crops in a plurality of curing barns or chambers. U.S. Pat. Nos. 3,910,757 and 3,972,674 illustrate this method and apparatus for curing crops. These same prior art patents also teach the concept of having a common heat source which can be selectively connected to one or more barns or chambers. The prior art has, however, failed to recognize the possibility for achieving substantial energy savings and other advantages by using a common heat source for bulk curing of crops with duct and control system which allows two or more chambers to be heated alternatively and in a predetermined repetitive time sequence when the chambers are filled with tobacco or another crop being cured or dried. More specifically, while the prior art has provided method and apparatus enabling a single heat source to supply heat to a plurality of barns or chambers simultaneously or to only certain of the barns at any one time, the prior art has not taught method or apparatus directed to utilizing a plurality of barns or chambers and cycling the heat from a common heat source to the chambers or barns on a predetermined, repetitive time schedule so that only one chamber or barn receives the heat at any particular time but all chambers or barns receive heat on a repetitive time sequence.